Most all organic polymers are non-conductive. Electrical conductivity can be introduced into these non-conductive materials by adding conductive fillers such as metal or carbon powders. Typically, only low loading of the conductive filler can be used before polymer properties begin to deteriorate. Further, it is difficult to control the exact conductivity of the final product because the material passes from the insulating state to maximum conductivity over a very narrow range of filler content.
A newer approach to conductive organic polymers involves the addition of a more or less reactive species, i.e., a dopant, to a conjugated or unsaturated polymer to oxidize or reduce it to the conductive state. This approach, however, leaves either negative or positive charges on the polymer which compromises the environmental stability of the system. Although a few of these doped polymers are stable in an ambient environment, most doped systems must be protected from the air, moisture and elevated temperatures or they rapidly lose their conductivity. Even the more stable doped polymers will lose their conductivity on exposure to more aggressive environments.
U.S. Pat. No. 4,336,362 to Walton discloses acetylene-terminated dianil monomers which are polymerized at a temperature below 150.degree. C. or, more specifically, in the range of about 130.degree.-140.degree. C., cured preferably in steps from about 150.degree. C. to about 300.degree., and postcured preferably in steps from about 400.degree. to 600.degree. C. These polymers, after postcure, are electrically conducting and can withstand high temperatures and wet environments. U.S. Pat. No. 4,116,945 to Griffith et al discloses bisphthalonitrile polymers which can be processed by conventional resin technology and which are electrically conducting.